In cellular networks such as Long Term Evolution (LTE) and LTE-Advanced communication networks, a user equipment (UE) may communicate with other UEs via a base station and an evolved packet core (EPC) network. For example, a UE may send data packets to its serving base station on an uplink. The serving base station may forward the data packets to the EPC network, and the EPC network may forward the data packets to another base station or to the same base station that is serving another UE. Data transfer between the UEs is routed through the base station and the EPC network. The communication between the UEs is controlled by the policies set by the operator administering the network.
The UEs may communicate directly with each other using another radio access technology (RAT), such as a wireless local area network (WLAN) or Bluetooth, when the UEs are located in close proximity and have access to the other RAT. However, this multi-RAT communication generally requires the availability of the other RAT and the capability of the UEs to operate in the other RAT. Moreover, handover from cellular technology to the other RAT may result in service interruption and dropped calls.